Bonsoir J'ai besoin d'aide Pour cet exercice Svp Merci d'avance

bonsoir

A = 8/3 - 5/3 : 20/21
A = 8/3 - 5/3 x 21/20
A = 8/3 - 105/60
A = 160/60 - 105/60
A = 55/60
A = 11/12

b = ( 2 + 2/3) : ( 4/5 - 2/3)
B = ( 6/3 - 2/3) : ( 12/15 - 10/15)
B = 4/3 x 15/2
B = 60/6
B = 10

C = 1/3 - 1/3 x 4/7
C = 1/3 - 4/21
C = 7/21 - 4/21
C = 3/21 = 1/7

D = 6/5 : ( 1/15 - 1/5)
D = 6/5 : ( 1/15 - 3/15)
D = 6/5  : - 2/15
D = 6/5 x - 15/2
D = - 90/10 = - 9